1. Technical Field
The preset invention relates to a managing structure for an umbilical member of an industrial robot.
2. Description of the Related Art
In an industrial robot (hereinafter referred to simply as a robot), a work tool is attached to an end of a wrist of the robot. In many cases, an umbilical member for the work tool (a cable and/or a tube; hereinafter referred to simply as umbilical member) for supplying material, energy or a signal (for example, air, electric energy, light energy or an electric signal) is arranged over a forearm of the robot and is connected to the work tool. Such an example of prior art is shown in FIG. 1.
In FIG. 1, numeral 1 denotes a robot controlled by a robot controller 2. A first wrist element 11 is mounted to a forearm 10 of the robot 1 and is rotatable about a first axis A extending in the longitudinal direction of the forearm. A second wrist element 12 is mounted to the first wrist element 11 and is rotatable about a second axis B generally perpendicular to the first axis A. Further, a third wrist element 13 is mounted to the second wrist element 12 and is rotatable about a third axis C1 generally perpendicular to the second axis B. A work tool H is attached to an end flange of the third wrist element 13. In this case, the work tool is a hand having suckers. Numeral 3 denotes an air delivery/suction device. An air tube 31 connected to the device 3 is joined in place to a cable 21 for supplying a power and an electric signal to the robot and is connected to a solenoid valve box 4. Delivery and suction of air between the solenoid valve box 4 and the hand H may be carried out by means of a tube (an umbilical member) 7. The robot controller 2 controls the air delivery/suction device 3 and the solenoid valve box 4 in a known manner, thereby delivery (grip-OFF) and suction (grip-ON) of air to and from the suckers of the hand H may be alternately changed.
In this case, disadvantageously, due to the rotation about each of the axes A, B and C1 by the motion of the robot, the umbilical member 7 may contact the forearm 10, may twine about the wrist elements 11 or 12, and/or may be strongly pulled. In order to avoid these disadvantages, in prior art, the umbilical member 7 has been widely outwardly projected before connected to the hand H, as shown in FIG. 1.
However, when the umbilical member 7 is widely outwardly projected, the action of the umbilical member 7 may be unstable when the wrist axis of the robot is activated. As a result, the umbilical member 7 may contact or interfere with a peripheral equipment and damage the equipment or the umbilical member itself. Another structure, in which an L-shape member 5 and an elastic body 6 are used so as to hang the umbilical member 7 above the forearm 10 and to limit the movement of the umbilical member, may be possible. However, the structure has in sufficient effect to avoid the interference.